Function Exec

io.go:107–160

Exec executes a system command and redirects the commands output to debug

(path string, args ...string)

// Exec executes a system command and redirects the commands output to debug
func Exec(path string, args ...string) error {
	if cmd != nil {
		return NewErrorf("Child process is aleady running (%s:%d)", cmd.Path, cmd.Process.Pid)
	}

	cmd = exec.Command(path, args...)
	defer func() {
		cmd = nil
	}()

	// parse stdout async
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return err
	}

	go func() {
		scanner := bufio.NewScanner(stdout)
		for scanner.Scan() {
			Dprintf("%s: %s\n", cmd.Path, scanner.Text())
		}
	}()

	// attach to stderr
	stderr, err := cmd.StderrPipe()
	if err != nil {
		return err
	}

	go func() {
		scanner := bufio.NewScanner(stderr)
		for scanner.Scan() {
			Dprintf("%s: %s\n", cmd.Path, scanner.Text())
		}
	}()

	// execute
	Dprintf("exec: %s %s\n", path, strings.Join(args, " "))
	err = cmd.Start()
	if err != nil {
		return err
	}
	Dprintf("exec: started with PID: %d\n", cmd.Process.Pid)

	// wait for process to finish
	err = cmd.Wait()
	if err != nil {
		return err
	}
	Dprintf("exec: finished\n")
	cmd = nil

	return nil
}